Column of alumina

Isopropyl methyl ether [598-53-8] M 74.1, b 32.5°nnmm, d 0.724, n 1.3576. Purified drying with CaS04, passage through a column of alumina (to remove peroxides) and fractional distn. 

Methyl vinyl sulfone [3680-02-2] M 106.1, b 116-118 /20mm, d 1.215, n 1.461. Passed through a column of alumina, then degassed and distd on a vacuum line and stored at -190° until required. 

Naphthacene (benz[b]anthracene, 2,3-benzanthracene, rubene) [92-24-0] M 228.3, m >300 , 341 (open capillary), 349 , 357 . Crystd from EtOH or benzene. Dissolved in sodium-dried benzene and passed through a column of alumina. The benzene was evaporated under vacuum, and the chromatography was repeated using fresh benzene. Finally, the naphthacene was sublimed under vacuum. [Martin and Ubblehode J Chem Soc 4948 7967.] Also recrysts in orange needles from xylene and sublimes in vacuo at 186°. [UV Chem Ber 65 517 1932, 69 607 7956 IR Spectrochim Acta 4 373 7957.]... 

Nitrotoluene [88-72-2] M 137.1, m -9.55° (a-form), -3.85° (p-form), b 118°/16min, d 1.163, 222.3°/760mm, n 1.545. Crystd (repeatedly) from absolute EtOH by cooling in a Dry-ice/alcohol mixture. Further purified by passage of an alcoholic soln through a column of alumina. 

Diisooctyl phenylphosphonate [49637-59-4] M 378.5, n 1.4780. Vacuum distilled, percolated through a column of alumina, then passed through a packed column maintained at 150 to remove residual traces of volatile materials in a countercurrent stream of N2 at reduced pressure [Dobry and Keller J Phys Chem 61 1448 1957]. 

Tri-p-tolyl phosphate [20756-92-7, 1330-78-5 (isomeric tritolyl phosphate mixture)] M 368.4, b 232-234 , d 1.16484, n 1.56703. Dried with CaCl2, then distd under vacuum and percolated through a column of alumina. Passage through a packed column at 150°, with a counter-current stream of nitrogen, under reduced pressure, removed residual traces of volatile impurities. 

Originally, p-tolylsulfonyldiazomethane was prepared by passing an ethereal solution of its precursor, ethyl i 7-nitroso-iV -(j3-toly]8ulfonyI-methyl)carbamate, slowly through a column of alumina, This procedure, which results in yields about 10% higher, is convenient only for small-scale preparations, up to a maximum of 5 g. of p-tolylsulfonyl-diazomethane. The present modification is due to Middelbos, ... 

At the same time, Dale and Kristiansen reported a successful synthesis of 18-crown-6 from the diol and ditosylate just as shown in Eq. (3.2), but using benzene as solvent. They obtained the product as its potassium tosylate complex (mp 164°) in 33% yield. The free macrocycle was liberated by chromatography over a column of alumina, eluting with a benzene-cliloroform mixture. Dale and Kristiansen note that the cyclic ether cannot be liberated from its complex by simple heating . ... 

Thus, the model compound 5a, 6a-epoxy-6j -methyltigogenin acetate (103) affords 3)5-hydroxy-6)5-methyl-10(5 6)crZ)eo-(25S)-spirostan-5-one acetate (104) in 90 % yield. As expected, the j9-acetoxy ketone (104) loses the elements of acetic acid on passing through a column of alumina to give 6)5-methyl-10(5 -> 6)-flZ>eo-(25S)-spirost-3-en-5-one (105). 

A short column of alumina may also be employed for decolorization. The colored solution is placed on the column and eluted with a dry hydrocarbon solvent. If the desired product is not highly polar in nature, recovery by the technique may be excellent. 

A mixture of 2.0 grams of 2,3-dihydroxylmino-17a -methyl-5a -androstan-17/3-ol, 5 ml of piperidine and 10 ml of ethylene glycol was heated at a temperature between 180° and 190°C for 30 minutes. After the resulting product was cooled, water was added thereto, and the separated product was filtered, washed with water and dried. The product was dissolved in benzene and passed through a column of alumina. The column was washed with ether, and the eluted fractions were collected and condensed. Subsequently, the residue was recrystallized from ether or aqueous methanol to produce 1.53 grams of 17/3-hy-droxy-17o-methyl-5o-androstano[2,3-C] furazan which has a melting point of 152°C. 

Alumina chromatography The butanol extract containing F is poured onto a column of alumina (2.6 x 9 cm Woelem basic alumina Grade 1), and F adsorbed is eluted with 50% ethanol containing 0.6% ammonium hydroxide. The fractions containing F are combined (a trace of Tris is added) and concentrated to about 5 ml, and mixed... 

The reaction mixture can also be processed by chromatography. The crude reaction mixture is poured on a 90-cm. x 4.5-cm. column of alumina (e.g, Fisher adsorption grade ) and eluted with about 2 1. of technical-grade pentane. This yields a pale-yellow solution that is free of diethyl phosphorochloridate. Evaporation of the pentane gives 240-255 g. (90-96%) of l,2,3,4,5-pentachloro-5-ethylcyclopentadiene. 

The checkers used 3-methyl-2-butanone purchased from Eastman Organic Chemicals. One sample that gave a positive test for peroxides was purified by passage through a column of alumina before distillation. The material was distilled routinely before use. 

The organic solvent is removed by distillation under reduced pressure to give 4,4 -dimethyl-l,T-biplienyl contaminated with a small amount of bis(4-methylphenyl)thallium bromide. The crude product is dissolved in 30 ml. of benzene, and the solution is filtered through a short column of alumina (Note 7) using a total of 250 ml. of benzene as eluent. Distillation of the benzene under reduced pressure leaves 19-21 g. (80-83%) of 4,4 -dimethyl 1,1 -biphenyl as a colorless solid, m.p. 118-120° (Note 8). 

Purification of 1,2-dibromoethane was accomplished by passing a small quantity rapidly through a 5-cm. column of alumina. Addition of 1,2-dibromoethane to the lithium dispersion is accompanied by visible evolution of ethylene (ethene). 

Check the column If there are air bubbles or cracks in the column of alumina, dismantle the whole business and start over ... 

The reaction mixture is transferred to a 2-1. round-bottomed flask, and the solvent is evaporated under reduced pressure (Note 8). The residue is dissolved in 50 ml. of warm cyclohexane (Note 2), and the solution (Note 9) is poured onto a column of alumina (Note 10) 1.8 cm. in diameter and 6-7 cm. in length. The round-bottomed flask is rinsed with three 10-ml. portions of cyclohexane, and the rinsings are poured onto the column. The column is eluted with additional cyclohexane (about 100 ml.) until no appreciable amount of 9-phenylphenanthrene is obtained in the eluate. The elution of any yeUow material from the column should be avoided. The total eluate is evaporated to dryness under reduced pressure (Note 8), and the residue is recrystallized from 40-45 ml. of 95% ethanol to give 1.65-1.90 g. (65-75%) of 9-phenylphenanthrene, m.p. 103.5-104.5° (Notes 11, 12, and 13). 

A solution of 0.005 mol of a sulfoxide, 2.26g (0.01 mol) of stannous chloride dihydrate, and 2.0 ml of concentrated hydrochloric acid in lOml qf methanol is refluxed for 2-22 hours. The mixture is cooled, diluted with 20 ml of water and extracted with two 25 ml portions of benzene. The dried extracts are evaporated in vacuo leaving virtually pure sulfide which can be purified by filtration of its solution through a short column of alumina and vacuum distillation or sublimation. Yields are 62-93%. 

---